DENVER (CBS4) – Marijuana may be legal in Colorado, but not necessarily on your license plate. In fact, CBS4 has found there are thousands of combinations of letters and numbers that are banned for vanity plates. Some are claiming it should be considered a violation of free speech.

Every car must have a license plate, but if you want to pay a little extra you can have a personalized one.

You can be “GOOROO,” proclaim your ethnic identity like one plate that reads “CUBANA” or support your favorite team like the one that reads “BILSFAN.” But CBS4 found there is a list of 10,000 combinations you cannot put on your Colorado vanity plate. One of them is “4TWENTY”, a reference to marijuana.

The vanity plate requests must be approved by the Division of Motor Vehicles which is part of the Colorado Department of Revenue. Lynn Granger is the spokesperson. CBS4 asked her what was wrong with a plate that reads “4TWENTY.”

(credit: CBS)

“It’s all in whether we determine it to be obscene … if it’s offensive in any way, once issued, if we receive complaints we relook at it and those plates may be recalled,” she said.